862 ANNUAL REPOBTS OF DEPARTMENT OF AGRICULTURE. 



made 0.75 Inch to 1 foot. The earth excavation comprised 75,S40 cubic yards; 

 the roclv excnviition, 5.420 ciii>ic yards; and surfacing material, 3,150 cubic 

 yards. The contract price per cubic yard for earth excavation was $0.27i : for 

 rock. $0.87; and for shaping the subgrade, $0.03 per linear foot. A total of 

 l.OnO cubic yards of stone masonry, at $5.50 per yard, cost $5,775; 10 cubic 

 yards of concrete masonry, at $G.50 per yard, cost $05; and 109 cubic yards of 

 reinforfod concrete, at $7 per yard, cost $70,3. ^L^cadam in place cost $1.50 

 per cubic yard, and 200 barrels of cement cost $1.75 per barrel. 



The total cost of the work was .$30,887, (U- about $2,000 per mile for earth 

 construction and $3,500 per mile for macadam construction. Included iu the 

 total cost are 4 concrete culverts and 20 bridges with stone masonry abutments, 



2 of which have steel spans of 50 feet and 1 of 40 feet. 



Brady, Tex. — The first section of a 29-mile road in Brady was started on 

 March 2, 1912, and completed on April 4, 1912. This section begins at station 

 264 and extends 26.400 feet northward toward Coleman. The grading was 

 made 45 feet wide in cuts and 25 feet wide in fills. The total area graded 

 was 117,300 square yards. The width from ditch to ditch was 45 feet. Plows 

 and scrapers were used for loosening material and 2 road graders, hauled by 

 a 20-horsepower traction engine, were used in surfacing. The crown of the 

 road was made 0.75 inch to the foot. The earth excavation amounted to 

 13.000 cubic yards and the rock excavation to 1,000 cubic yards. The average 

 haul was 200 feet, the maximum 500 feet, the average cut 1.5 feet, and the 

 maximum grade was reduced from 8 per cent to 5 per cent. Three thousand 

 four hundred and fifty-two feet of this section was rock, and the remainder 

 clay loam with a small percentage of sand or soft limestone. Nine wooden 

 culverts, each 24 feet long, were built of various sizes ranging from 1 foot by 



3 feet to 4 feet by 6^ feet. 



These culverts contained 9.810 feet b. m. of lumber. Two double metal cul- 

 verts, each 22 feet long and 2 feet in diameter, were also placed in position. 

 All the wooden culverts have dry rubble wing walls which contain altogether 

 24.6 cubic yards of masonry. The two corrugated metal culverts have dry 

 rubble mpsonry end walls 20 feet long, 2 feet wide, and 3 feet high, containing 

 9 cubic yards of material. Five of the culverts are paved 6 inches deep, making 

 the total amount of paving 12 cubic yards. 



The cost of the work was $2,300.76; the cost per square yard. $0,196; and 

 the cost per mile, $400.15. Labor cost $1.05 per day, and teams .$3.50 per day. 

 Some of the unit prices were as follows: Earth excavation, $0.09 per cubic 

 yard; rock excavation, $0.50 per cubic yard; end walls and paving, $1 per cubic 

 yard; the traction engine and grader, $18.50 per day; dynamite, $0.1275 per 

 cubic yard of rock; $25 per thousand feet of lumber b. m. : and the preliminary 

 survey, machinery, tools, etc., $4,000, 7} per cent of which, or $285.71, was 

 charged to this work. 



EXPERIMENTS AT CIIEVY CHASE, MD.* 



The work at Chevy Chase is the beginning of a series of thor- 

 oughly organized experiments in road construction which have been 

 made possible through the appropriation by Congress of a special 

 fund for carrying on such work. The project for the current fiscal 

 year consisted of a series of comparative tests of bituminous binders 

 now on the market, applied according to the specifications of the 

 manufacturers supplying them. The road selected is an extension 

 of Connecticut Avenue, Washington, D. C, and the work thus far 

 completed begins at the District line at Chevy Chase Circle and ex- 

 tends to Bradley Lane, a distance of 3,300 feet. There are eight dis- 

 tinct sections in which various bituminous binders were used, and a 

 section of water-boimd macadam upon which experiments in surface 

 treatment are being conducted. A systematic traffic census and ac- 

 curate costs for maintenance and repairs are now kept. 



1 See Circular 98, Office of Public Roads, United States Department of Agriculture, for 

 full details of these experiments. 



